Railway braking apparatus



Oct. 5, 1943.

s sheets-sheet 1 Filed April 1s, 1942 w J 5A/@ W v, mi w M, 4 HL W m 4 Wy wk Y f FVM A Q ww ma n l u F .r n 5w @n Am www www rril IIIFIIll/Ar f.www QRNQ w Qwmw www@ www www www TLA Oct. 5, 1943. J. w. LOGAN, 'JR

RAILWAY BRAKING APPARATUS 3 Sheets-Sheet 2 Filed April 18, 1942 Oct. 5,1943. J. w. LOGAN, JR

RAILWAY BRAKING APPARATUS 3 Sheets-Sheet 5 Filed April 18, 1942 [ammi:

e m m w. f ffm y @fo W0/ dal. l d MMw/ @MmmmPm/M/yoo??66655554144444453573 nr? o d, Z @Umb N fmf w @my U U .I M L ,rf n Patented Oct. 5, 1943 UNITED y STATES PATENT' Y vOFFICE p rv Y n .Yf Y 2,331,125 t Y I y RAuWAyBnAKING APPARATUS j Joh-n W. Logan, Jr.;ForestHills, Pa., assignor to The` Union Switch &, Signal Company,Swissva-le, Pa.,` a. corporation of Pennsylvania Application April 18,1942,'Se1'ial`No. 439,582I

` 12 Claims. .(Cl.. 303-21) My invention relates to railway brakingapparatus, and particularly to car retardersuofv the type comprisingwheel engaging braking -bars located beside a track rail and movabletoward and away from the railinto braking and nonbraking positions.`More particularly, umy invention relates to apparatus of the typedescribed wherein the braking bars are arranged tolbe moved to theirbraking positionsuby one or more iiuid pressure motors and to berestored to their non-braking positions by suitable biasing means.

One object of my invention is the provision'o'f y improvedmeans forautomatically controlling thebrakng action of a car `retarder of thetype described in accordance withthe'sp'eed and weight of a car passingtherethrough. y t Anotherr object of my invention is to provide acontrol system for Acar retarders of the type described which willcausecars to leave the retarder at a speed which is` inversely proportionalto the weightl of the car, whereby light cars will leave the retarder ata higher speed than heavy cars.

Apparatus embodying my invention-is an improvement upon that describedand claimed in an application lforLetters Patent of VtheUnif-ed States,Serial No. 424,338,1led'by Clarence S. Snavely, on December 24, 1941,-for Railway braking apparatus,

According' to my invention, a stretchof track with which the retarder isassociated is divided into short track sections cistron lengths that twowheels of a car cannot roccupy apsectionat a time, and each tracksection has associated therewith a tracl; relay which becomes energizedwhenjand only when the associated section is occupied by. the leadingpair of wheelswithin the l,reta'rde'r'of a car being retarded bytheretarder. When anyy track relay is. energized, it sets intooperation. speed `responsive means including a unit and multiple chainof counting relays wherebythespeed of the car is determined. n' f Thestretch of track with which. the' retarder is associated also hasassociated therewith means for selectively operating va pluralityofcontacts in accordance with the weight of a car entering the retarder,which contacts together with contacts of the track relays control aplurality of;

the unit and multiple chainsl together control other relays whichcontrolthe supply ,oiffluid.' ,Y pressure tothe car retarder in suchmannerth'atthe retarderwill exert abrakin-g forcerfwhich is inverselyproportionalto the-weight of the car being retarded, whereby heavy carswill leave the retarder "at a relatively low-4 speed andlightcars atarelativelyfhigh speed. f This control is de.

sirablef'in1 orderto obtain uniform coupling speeds n when lthe carsreach their destination in the classica'tion tracks ora gravity typ'ecarrretarder Yard Since Vthe kcar 1 resistance of.y iight cafsqis greaterthan that of heavy cars.- i i f Otherobjects and characteristic featuresof i' my l invention will "become apparent as""fthe 1de'- scriptionproceeds. i "f one formA of railway `braking fI' shall describeapparatus vembodying VVmy invention.` and shall weight Aresponsiverelays. The. control ofthe weight responsive relays is such thatVthesefrelays will selectivelyv pick up in jaccordancewith the leaves theretarder. v v v f The weight responsive relays and the relays of thenpoint ont the novel'A features V`thereof in claims. j s l A` Inftheaccompanying drawingaiiigs. la'jand lb arefviews whichwhen placed voneabove 4theA other with'Fig. la on topl in such manner that the dottedlines leading to the bottom ofFig. 1a alignfwith the dotted linesleading to the top of Fig. lb, togetherconstitute a view -partlysectioned and partlyV diagrammatic illustrating one form of apparatusembodyinglmy invention. Fig. 2 is a table showingthe method ofconnecting the Afront contacts of certain ones of the relays formingpart of the apparatus illustrated in Figs;

la and 1b to obtain predetermined controlA speeds.

Similar reference parts in both views.,- A.

Referring iirst to "Figs, la'and'lhthe reference characters I and I adesignate the track rails of a stretch of railway track over which carsnor# characters""referA :to similar mally move in the directionyindicated bythe arrow under such conditions that it is desirable' toatftimes control'the speed of the cars automatically. For' example, @thestretchv of trackv here shown might be in a classicationyard of the humptype through which cars Iriove under the influence of gravity.l It isobvious that in service of thiskind` the speed of individual cars orstrings of cars willvary" through Wide limits' depending amongotherthings on the speed! at which they go over the hump thetemperature,v the weight of the car andits contents,-and'the f conditionofthe caras to whether it is a yfree-niniv ning car or otherwise. f n VInY order to control the speed of the cars; fthe stretch' crtrackiuu'stratedin thejrawingsyis .v provided with a car retarder'CR.which'inthev form here shown comprises two brakingfbars 2' j and 3extending parallel with, and located on opposite sides of rail I, andtwo similar braking bars 2a and 3a extending parallel with and locatedon opposite sides of rail Ia.

The braking bars 2, 3, 2a and 3a are operated by a uid pressure motor M(Fig. 1b) comprising a cylinder 4 containing a reciprocable piston 5attached to one end of a piston rod 6. The braking bars 2, 3, 2a and 3aare operatively connected with the piston rod 6 through a suitablelinkwork here shown as comprising a bell crank I and a lever 8 pivotallysupported at point 9. When piston 5 occupies its extreme left-handposition, in which it is illustrated in the drawings, the braking barsoccupy'A their non-braking or ineffective positions in which theyv areout of engagement with the wheels of a car traversing the rails I andIa. When piston 5 is moved to its right-hand position, however, as whenAfluid,

pressure is admitted to the left-hand end of cylinder 4, the brakingbars4 2, 3, 2a and 3a are moved toward the associated rails to theireffective or braking positions in which they will engage ythe wheels o-fa car traversing the rails, I and I a, to-retard` the speed of. the car.

The braking bars 2, 3, 2a, and 3a are constantly biased to theirnon-braking positions by any suitable. means, here shown as a spring Iwhich is interposed in the cylinder 4 between the right'- hand end ofthe cylinderand the piston The motor M is controlled by two magnetvalves VI and V2, each comprisingl a valve stem I2 biased to an upperposition by means of a spring, U, and provided with an armature I3 and awinding I4. When valve `VI is energizedas shown in the drawings, valve,`stem` l2 of this valve is moved downwardly lagainst the bias of springIl, and a pipe 8 which communicates with the left-hand end of motor M isthen connected with atmosphere through a port I5. When valve VIl isdeenergized, however, pipe I8 is disconnected from atmosphere, and, is.connected with a pipe I6k leading to valve V2. When valve V2 isenergized, valve stem I2 of this valve moves downwardly, and connectspipe t6 with a pipe |71 which is constantly supplied with fluidpressure, usually air, from a suitable source not shown in the drawings,but when valve V2 is deenergized, as shown in the drawings, pipeA Hi isthen disconnected from pipe Il. It will be apparent, therefore, thatwhen valve VI is energized, the region of the cylinder 4 of motor Mbetween the piston 5. and the left-hand end of ther cylinder isconnected with atmosphere, so that the brak-Y ing bars of the carretarder Willthen be held in their ineffective or non-braking positionsby the spring ID. When, however, valve VI is deenergized, and valve V2is energized, uid pressure will be supplied to theleft-hand end ofcylinder 4 of motor M, thusk causing the braking bars to move to theireffective or braking positions. It will be obvious that when the brakingbars are moved toy their braking positions, they will exert a brakingforce` which is proportional to the pressure of the fluid which is thensupplied to the right-hand end of motor M. Y

The valves V are controlled in part by a plurality of pressureresponsive devices P20- 30 and P4B-55s each comprising a Bourdon tube 2|connected to pipe i8 and. hence subjectedrto the pressure of the fluidin the left-hand end of motor M, Each Bourdon tube controls twoccntacts- 22-22a and 2-2-2217. The pressure responsive devices P20-33and P45-55 are so constructed and so adjusted that they will operatesuccessively as the pressure in the region of cylinder 4 between thepiston 5 and the lefthand end of the cylinder increases. For example,for all pressures below pounds per square inch,

kthe contact 22-22a of each of these devices is closed. If the pressureexceeds 20 pounds per square inch, however, the contact 22-22a of deviceP2El-3i) opens, and if the pressure exceeds A30 pounds per square inch,contact 22a-22D of i cie pressures are not essential but are onlymentionedfor purposes of explanation.

The valves V are also controlled in part by two relays IP and IPO whichrelays, in turn, are controlled by speed and weight responsive apparatusin a manner which will he described in detail hereinafter.

The valves V are further controlled by means of a manually operablelever L which, as here shown, is capable of assuming three positions,indicated by dotted lines in the drawings, and designated by thereference characters p8, pl and p2, respectively. Operatively connectedwith the lever L` are a plurality of contacts 25, 2l and 29` Contactsl5,Y and: 2l are closed, respectively, in the pil andpI positions oflever L, while contact 28 is closed in the pI position, the p2 position,or any position intermediate these two positions.

The lever L will usually be located at a point remote fromv the brakingapparatus, as in the control cabin of a classification yard car retardersystem, and will be connected with the braking apparatus. by means ofline wires extending from the control cabin, to the braking apparatus.

The valves V are still further controlled in part by a relay LPwhichprovides a means for at times changing the general level of theyfluid pressure supplied to the uid pressure motor M, That is to say.,when this relay is deenergized, the pressure responsive devices P20-3Dand 1345-55 are rendered ineffective to control the valves V, and ifthe` valve V2 is energizedunder these condi tions motor M will besupplied' with fluid at full line pressure. When, however, relay LP isenergized, the pressure responsive device P20-39 or P45--55 will then berendered effective to control the valves VI and V2, depending uponwhether relay I'P isrthen picked up or released.

The relay LP is controlled in part by the lever L and in partv by theweight responsive apparatus, in a manner which I shall describe indetail hereinafter.

'I'he previously mentioned speed responsive apparatus for controllingrelays IP and IPO comprises. a series of relatively short insulatedcontrolV sections IT, 2T, 3T, 4T, 5T and 6T, which control sections areformed in the rail I. These control sections will usually be of uniformlengths, and their lengths may be varied as conditions require, but thelengths of these sections will preferably be such that two wheels of acar cannot occupy the same section at any one time. A preferred lengthfor these sections is 3 ft. 11/2 in.

Associated With each control section is a track relay designated by thereference character R with a prefix corresponding to the referencecharacter for the associated section. These track relays are sensitivequick actingl relays, and each relay is controlled by suitable trackcircuits not shown-in'such manner that each relayf will be,

energized when and only'when' the associated control section is occupiedby the leading pair 'of wheels within the retarder of` a car passing"Vthe car. Thismeans forms no part of my present invention, and may,.forexample, be similar to that described and claimed in the aforementionedSnavely application, Serial No. 424,338. Assuming that this meansissimilar in all respects to that shown in the said Snavely application,it is believed to be sufcient for purposes of mypres'- ent invention topoint out that this means includes a unit chain of counting relays IU`to 6U which operate in succession vat predetermined intervals when anytrack relay isgenergized and a multiple chainof counting relays IM to Mwhich operate in succession, one for each round trip of operation of theunit chain. A new operation/oi both chains is initiated each time a newtrack relay picks up, which new operatlon'necessitat'es that all of therelays of both chains be initially n deenergized. The time intervalwhichelapses bef tween the picking up of successive relays of the unitchain may have any desired value, but for cupiedwithan average car speedof 8 miles per hour, when the'section becomes vacated, relays 2M and4Uwill be picked up,.anditfollows'that if ythese relays are picked upwhen a measuring sectionbecomes vacated, it is an `indication that thecar which caused them to pick up was travell fing' at 'an averagespeedfof 8 miles per hour.

purposes of illustration I shall assume that this interval is 16%milliseconds, withthe resultthat the unit rchain will complete a roundtrip of operation in exactly 100 milliseconds. Based on this assumption,the picking upof eachprogressive relay of the multiplechainrepresents aperiod of-lOO milliseconds, and it followsthat provision is made forcounting up to 500 milliseconds by the picking up of the M relaysafterwhich, of course, another 100 milliseconds may be countedhypermitting another round trip of the unit .,chain,A

making a total of 600 milliseconds..

Therelays of the .unit and multiple chains each operate a plurality ofcontacts as ,will be Aseen from an inspection ofthe drawings,... y

It will be obvious that with the time measuring means TMM controlled inthis manner, the par- Similarly, vif atr'ack section 'which is servingas`a measuring section is'occupied for 600 milliseconds; which correspondsto a'car speed of 3.1 miles per hour, relays 5M and 6U will be picked upto indicate that the car speed is 3.6 miles per hour.

The carspeeds corresponding to various *relay* f 4combinations arekshown in tabular form in Fig.2, and by reference to .this table the carspeed `for any particular relay combination can be determined.

,The weight responsive apparatus referred lto hereinbefore forcontrolling the relays' IP, IPOl I and LP comprises a weightresponsivecontacter WRC arranged to be operated by cars passing through theretarder. This contacter may assume a variety ofdii-ferentconstructions.` For example, it maycomprise a scale whichweighsthe cars and which selectively operates contacts inaccordy ancewith the car weight pro-vided the car weight exceeds avpredeterminedminimum weight. `Alternatively this contactor may comprise a circuitcontroller operated bythe deflection of one of the track rails to causeit to selectively clo-se its Y contacts in accordance with the carweight pro(- vided the weight ofthe car which caused there-il;-deflection exceeds a predetermined minimum weight. As's'hown inthe'drawin'ga-this contactor comprises a movable contact member 250biasedv to an upper position by means of a spring 25|, and operativelyconnected with the rail Ia opposite to the track vsection 'IT in suchYmanner that when the section IT is occupied'by afycar, the Y spring willdeflect and 'will'permit the contact member to move downwardly an amountwhich is u proportional to the car weight. The movable ticular relaysofthe unit and multiple chains l which are picked up at any onetime areameasure of the time that 'any section which is then functioning as ameasuring section has beenoccupied.

It will` also be obvious that sincethe sections have a known fixedlength, the speedoffa car passing through the carA retarder can bedetermined from the time during which a section is occupied by a pair ofwheels. 'It followsytherefore,that, the relays of thecountingchainswhich are picked,v

up when a pair of wheels vacates asection which is then functioning asLa measuring section serve as a measure of the average car n car istraversing .a length equal to the lengths of the measuring sections. Forexample, assuming that the trackisections T are all 3 it. 11/2 in. long,and that the relays ofr chains operate at the time yintervals designatedabove, if a track section remains occupied for 266 milliseconds, whichisthe time it willremain` ocspeed while the the unit `land multiplecontact250 cooperates with fourstationary con-r tact ymembers 252,253', 254'and 255m such mann ner that as it moves downwardly, it .will conestantlyfengage the member 252 and will rselectively engage the contactmembers 2453, 254* and 255 to 252-250-255 depending upontheextent of thedownward movement. -By properly proportionin'g the parts, the contactsmay be madeA to become closed at any desired car weights7 which for pur"poses of illustration I shall assume to be 35A tons for'the` Contact2524250-253, 50 tons for the rThe contactorV WRC together with'thetrackre-I lays TR control a pluralityoir weight responsive relays WM5, was!!and wRin;Re1ay waas is provided with a pick-up circuit which passes fromterminal B of a suitable source of current not shown in the drawings:through wireZE, contact 252-250-253 of weight" 'responsive contacto'rWRC, wire 26|, the windingof relayfWRS, backcontaer 262 of relay wasnand backcorntact 263,) Y*

of relayWR'IIl to terminal C of the source.` Relay "WR-35 is alsoprovided With a plurality oirstick;y circuits each of which passes fromYterminali?,`

through afront contact 264 of a different one "of the track relays ITRlto STR, inclusive, front. contact 265 of relay WR35, the winding of4relay WR35, backl contact 282 of relay WREG and backcontact 263 ofrelay WRI!) toterminal C. y

Relay WRll is provided with a pick-up circuit,

which passes'from terminalB through `wire 250,

contact 252-2511-254 of'weight responsive :contactor WRS, wire 26,5, thewinding of relay W-R and back Contact 263 `of relay WR'I0 -to terminalC. Relay WRO is also'providedwith a plurality of stick circuits each ofwhich passes from terminal B through a front contact 264 of a different4one ofthe trackrelays `front contact 251 of relay WR5D,-the Winding of'relay WRSIJ and `front contact' t3 of relay WE1@ to terminal C.

Relay WR113 is provided Withfa pick-,up circuit which vpasses fromterminal B throughiwire V260, contact v'1252-250--255 of weightresponsive contactor WRC, Wire 268 and the winding of relay WR'I toYterminal C. -Relay WRflIlfis further provided With a plurality of stickcircuits each of which passes from terminal B through a front contact264 of a different `oneof the track relays TR, front contact 2690i relayWR'IU and the winding of relay WRID to terminal C.

With the Weight responsive relays controlledin this manner, it will beapparent that when a car enters the retarder if the car Weighs less than35 tons, none of the contacts of the weight responsive contacter WRCwill become closed and all of the weight responsive relays will remaindeenergized. If, however, a car which Weighs more than 35 tons, but lessthan 50 tons enters the retarder, contact 252-250-253'Wil1 become closedand Will complete the pick-up circuitl for relay WR35, thereby causingthis relay to become energized. As soon as thisA relay becomesenergized, one of its stick circuits will become closed at its frontcontact 255, and as the car moves through the retarder, other onesof itsstick circuits will become closed, with the result that this relay willsubsequently remain energized until the car leaves the retarder.

In a similar manner, if a carA Weighing more than 50 tons but less than70 tons enters the retarder, the pick-up circuits for both of the relayslli/R35 and WR50 will become closed. This will cause both of theserelays to pick up, but as soon as relay WR'ID picks up it will interruptat its back contact 262 the Vpick-up circuit and all of the stickcircuits for relay WR35, and this latter relay will thereforeimmediately release. When relay WREII once picks up, it willsubsequently remain picked up, by virtue o'f its stick circuits, untilthe car which caused it to pick up leaves the retarder,

When a car weighing more than 70 tons enters the retarder, the pick-upcircuits `for lall three relays WR35, WREIJ and WR'IU will becomesuccessively closed, and Vall three of these relays Will becomeenergized. Relays WR35 and WR50, however, will immediately becomedeenergized since as soon as relay WR1U picks up, al1 circuits for theserelays Will be interrupted at back contact 263 of relay WR'ID. Whenrelay WR'IU becomes energized, it Will of course remain energized byvirtue of `its stick circuits until the car which caused it to becomeenergized'leaves the retarder as is obvious.

The Weight responsive relays WR35, WR55 and WR'IO, and the relays of theunit and multiple counting chains together controla plurality of pick-upcircuits `for each of the pressure control relays IP and IPO. .As Willappear presently, the relay IP functions when it becomes energized toreduce the braking pressure exerted by the retarder, While the relay IPOis effective when it becomes energized to fully release the retarder.The pick-up circuits'for the relays IP and IPO are preferably soarranged that for each car speed atwhiclrrelay IPO is caused to vpickup, the relay -IP will be'caused to pick up at a slightly higher car'speed, whereby an automatic stepped reduction in the pressure of theiluid supplied :tomotor Mis obtained prior to actually releasing theretarder. The number of control speeds that are provided for anyparticular yard installation will depend upon the variety of the weightsof the cars which are to be retarded, it being in'general desirable thatthe speedat which heavy cars are permitted to leave the retarder shouldbe less-than the speed at which lighter cars are permitted to leave theretarder since the car resistance of light cars is greater than that ofheavy cars. As here illustrated, three pick-up .circuits have beenprovided for each of the relays IP and IPO to enable three differentleaving or `control speeds to be obtained, one for light cars, that is,cars weighing less than 35 tons, one for medium -Weight cars, that is,cars Weighing between 35 and 70`tons, and one for heavy cars, that is,cars Weighing more than '70 tons. The actual car speeds at which thesecircuits become closed will depend of course upon the ,particularcontact combinations of the U and M relays which are included in thesecircuits, and may be varied to suit the conditions of grade, length ofclassication tracks, direction and velocity of the prevailing Winds,general temperature conditions, etc., .encountered in any particularyard layout to which the system isapplied. As here illustrated, thesecircuits are so arranged that when a light Weight car is being retarded,the relays IP and IPO will pick up when the car speed has been reducedto 11.6 and 6.7 miles per hour, respectively; when a medium Weight caris being retarded, the relays IP and IPO will pick up at speeds of 9.8and 5.8 miles per hour, respectively; and when a heavy car is beingretarded, the relays IP and IPO will pick up at speeds of 9.1 and 4miles per hour, respectively.

Included in the pick-up circuits `for the relays IP and IPO are stickrelays ISP and ISPO the functions of which Will be made clear presently.

To facilitate connecting the desired contact combinations of the U and Mrelays of the unit and multiple counting chains in the pick-up circuitsfor the IP and IPO relays to obtain the desired control speeds each ofthe contactsof the U and M relays are permanently connected to adifferent pair of terminal posts mounted on a terminal board TB (Fig.1b). This terminal board is also provided with other terminal posts suchas the terminal posts 8| and 83 to which jumpers, such as the jumpers II9 and |50, may be attached, and which are permanently connected in thepick-up circuits.

Considering now the pick-up circuits for the relays IP and IPO indetail, the pick-up circuit which is eiective for controlling relay IPwhen a light weight car is being retarded by the retarder passes fromterminal B of .a suitable source of current through contact 21 of leverL, Wire 215, a back contact 21B-216D of each of the Weight responsiverelays WR35, WR50 and WRIEJ, wire 211, terminal post 8l, jumper I I9,front contact of relay 5U, jumper |20, front contact 'I8 of relay IM,jumper I2I, terminal post 93, a

resistor 2I9 and the winding of relay IP in series connected in multiplewith a resistor 220 and a condenser 22I in series, and the'winding ofrelay ISPv to terminal fC of the source.

The pick-up circuit which is effective for controlling relay I'PO whenalight weight car is i being retarded by the retarder, passes fromterminal B through contact 21 vof lever L, a back kcontact 21S-2161) ofeach of the weight respon- Winding of relayV IPO in series connected inmultiple With a resistor 223` and a condenser Y221| in series, and theWinding of relay. ISPO to terminalC; The pick-up circuit which iseffective for controlling relay IP when a medium weight car is beingretarded bythe retarder passesfromaterminalB through contact21 of yleverL, wire 215, front contact 216+216a of relay WR35or"back contact 21S-2161) of relayWR35 and front'contact V21I,-21I5'a of relay WR50,.Wire218, terminalr post 84, jumper. |63, frontcontact 15 of relay IU, jumper|64, front contact 18 of relay 2M,"jumper |65, terminal post 94,resistor 2I9and the winding oi?V relay Ilfhinv seriesconnected inmultiple with resistor 220 and condenser 22| in series, and the windingvof relay ISP :to terminal C.

The pick-up circuit which is effective for conv trolling relay IPOy whena medium Weight car is being retarded by the retarder passes fromterminal B through contact 21 of'lever L, wirev 215, v front contact21E-21Go of relay WR35 or back contact 21S- 2161) of relay `WR35 andfront contact 21B-16a of relay WRSIJ, Wire 218, terminal post 85, jumper|68, z'frontfcontact 80 of vrelay 4M, jumper |69, terminal .post |00,resistor 222 and the windingof relay IPO in series connected in multiple.with resistor 223 and condenser 224 in series, and the winding of relayISPO to terminal C. g y i I i The pick-up circuit Which is effectivefor'controlling relay IP when a heavy car is being Lretarded by theretarder .passes fromte'rminal B through contact 21 of lever Il; wire215, back contact 21E-2161)` of relay WR35; back' Contact 21S-21Go ofrelay WBSO,- front contact 2164-2161; of relay WRJU, Wire 219,',terminalpost 81, jumper |13, front contact'16` ofrelayfZU, jumper |14, frontcontact y35| of'relay 2Mf,-'jurnper |15, terminal post 95, resistor2|9and` the Vwinding of relay IP in series connectedin multiple withrre- 'sistor 22|! and condenser 22| in series, and theA winding of relayISP to terminalC. The pick-up circuit which is eifective' forcontrolling relay IPO when a heavy caris being retarded by .the retarderpasses from terminal B through contact 21 of lever'L, 'wire1215, backcontact 21B-2.151) of relay WR35, back contact 2167-2161) of relay WR50,fronty contact 216-21Ba Vof relay WR1Il,wire 218, terminalpost 8B,jumper m5 front contact 11 of' relay 2U, jumper |06, front contact 80 ofrelay 5M, jumper |81, terminal post I Il I, resistor 222 in series withthe winding of relay IPO connected in multiple` with resistor 223 inseries with condenser 224, and the winding of relay ISPO toterminal C.j. 'n n y Y It will be noted thateach of the pick-up circuits justdescribed for both thev IP( and IPO relays includes -contact. l21,-oflever L, and it iollows, therefore, that these circuits, are effectiveto control kthese relays when andonly when lever L occupies its pIposition. Y

`1|;,Will alsovbe noted that since relay ISP is included in each of thepick-'up crcuitsfor relay IP, relay ISP will become energized whenever lrelay IP becomes energized. Likewise;` since relay ISHPO is included ineach ofthe pick-.up circuits for relay IPO, relay` ISPO will becomeenergized Whenever relay IPO becomes energized.

Relay IP is also provided with a plurality of stick circuitsv'each. ofwhich includes a front-contact 2I5of a-,different one of the relays IUtovSU of the unit L chain, wire 2I6, back contact 2I1- 2I1a or relayISPO, ywire-23|, front contact |30 of relay |SP,kfront contact |lil ofrelay c IP,

resistor 21,"9 inseries with the Winding ofrelay IPL connected in'multiple withresistor 220 ,in series with condenserV 22| and theWinding vof -relay ISP to terminal C. It Will be apparent, therefore,,that when relay -IP becomesrenergized by virtue of the completion ofany one of its pick-up circuits, it will subsequently be held'energizedover one of its stick circuits as long as the track circuit theoccupancy of which caused it to'bed that 2I8 of4 relay IPO, re'sistor222in series with the ,t

winding of relay IPOconnected in multiple. with resistor'223 in serieswith condenser 224,` andthe winding of relay METRO to terminal C.'Itfollows that when relay IPO becomes energized by'virtue of thecompletion of anyone Y.of its pick-up circuits,,it will subsequently beheld energized by .virtue of one of its stick circuits as` long as thetrack circuit the occupancyof `which caused Yit to become energizedremains occupied. z

It will be rememberedthata new speed measurement `is mader each time theleading pairof wheels of a car passes-from one `track section toanother, and it isobvious that each time a new speed measurement is-made a time-intervalwill elapse during which al1 of the pick-up andrl`stick circuits forythe relays IPgand` IPO will be open. VTo obtainsmooth operation of theretarderit is necessarythat. when either one ofthe relays IP leasing to bridge the interval between successive speeddeterminations., Ashere shown,V these re- -f lays are renderedsufliciently; slow releasingftjo `bridge this interval by storingaenergy .in the con,-

densers 22| andl224. which are shunted,r around the relays IP and IPO inseries with the associated resistors, Condensers are used because theyguarantee a denitetime element inl'afshorter space of timefthan ispossible with schemes-,utilizivnglthe saturation of the relay to obtainthetime ,.element.

Thev stick relays ISP and ISPO are provided Aprevent the relays IP and`IPO from startingftheir slowlreleasing period atthe time of their: pickgv up insteadfof Waiting until the track ksection, the

occupancy `of whichlrcaused them to pickup is vacated. Thus, it will beseen that the; relaysjISP and ISPO on each` successive speed measurement:serve .to Vmaintain energy on the associatedpressure control relay IPorA IPO from the time` suchV relay becomes' energized4 until such Atime"assthe nexttrack relay becomes energizedat which time the resultantdeenergization of allof the relays. lof theunit chain will/'interrupt`the stick vcircuits iorfthese pressure control relays andjwill1rtherefby permit the condenser associated with the ener,-,gizedpressure control relay to function todelay the release of therelay until a new speed measurement is completed. f

The relay LP is provided with an energizing circuit which passes fromterminal B through contact 29 of lever L, wires 28l and 282, a backcontact 280 of each of the relays WR50 and WR'N, wire 2l0 and thewinding of relay LP to terminal C. It will be seen, therefore, thatwhenever lever L is moved to its pl or p2 position, relay LP will becomeenergized and will subsequently remain energized until either one of theweight responsive relays WR50 or WR10 picks up. 'Phat is to say, whenlever L occupies its pl or p2 position, relay LP will be energized atall times when cars Weighing less than 50 tons are traversing theretarder, and will be deenergized when cars in excess of 50 tons aretraversing the retarder. The actual car weight just mentioned abovewhich relay LP will release is of course arbitrary, and

can be varied to suit conditions by providing for L the control of thisrelay Weight responsive relays which will pick up at the desired carweights if such relays are not already available.Y

As shown in the drawings, all parts occupy the positions which theynormally occupy when no car is passing through the retarder, that is tosay, all relays are deenergized, lever L occupies its p or ofi position,and valve V2 is deenergized. Valve Vl, however, is energized over acircuit which may be traced from terminal B of the source throughcontact of lever L, line wire l l5, wire 203, and the winding of valveVl to terminal C. As was pointed out hereinbefore, when valve V2 isdeenergized and valve Vl is energized, cylinder 4 of motor M isdisconnected from the source of iiuid pressure and is connected withatmosphere, and the braking bars are therefore held in their ineffectiveorV non-braking positions by the spring l0. The contact 22a of each ofthe pressure responsive devices P is` closed, and the contact 22-22b ofeach of these devices is open.

In explaining the operation of the apparatus as a Whole, I shall assumethat a car which Weighs less than tons is approaching the retarder, andthat the operator wishing to cause this car to leave the retarder whenit has been slowed down to the proper control speed moves lever L fromits p0 or off position to its pl or normal control position. Themovement of lever L from its p0 to its pl position will interrupt at itscontact 25 the circuit which was previously closed for valve Vl, andwill complete at its contact 29 a circuit for valve V2 which circuit maybe traced from terminal B through contact 29 of lever L, wires 28| and235, back contact 23l--23lial of relay IPO, back contact 23T- 231e ofrelay lP, back contact 238-238a of relay LP, wire 205 and the Winding ofvalve V2 to terminal C. Valve Vl will therefore become deenergized andwill disconnect cylinder 4 of motor M from atmosphere, and valve V2 Willbecome energized and will connect cylinder 4 with pipe l1, therebyadmitting fluid to cylinder 4 at full line pressure. The movement oflever L from its p0 to its pl position also completes at its contact 29the previously traced circuit for relay LP and this relay thereforeimmediately picks up. As'soon as this relay picks up, it interrupts atits back contact 238-238a the circuit just traced for valve V2, andcompletes at its front contact 23R-23B!) another circuit for valve V2which latter circuit may be traced from terminal B through contact 29 oflever L, wires `28l and 235, backcontact 23S-23M of relay IPO, backcontact 23'l--231a of relay lP, front contact 23E-2385 of relay LP,

wire '239, contact 22-22a of pressure responsive device P-55, wire 205and the winding of valve V2 to terminal C. By virtue of this lattercircuit valve V2 will remain energized until the pressure of the fluidin motor M increases to 45 pounds per square inch at which time Contact22-22a of pressure responsive device 1245- will open and will deenergizevalve V2. If the pressure of the iluid in motor M now increases to 55pounds per square inch for any reason, contact 22-22b of pressureresponsive device P45--55 will become closed and will complete acircuitfor valve Vl passing from terminal B through contact 29 of leverL, wires 28| and 235, back contact 236-236a of relay lPO, back contact231-23711 of relay IP, front contact 23R-2381) of relay LP, wire 239,contact 22-22b of pressure responsive device P45-55, asymmetric unit 206in its low resistance direction, and the Winding of valve Vl to terminalC. Valve Vl will therefore become energized and will vent fluid frommotor M until the pressure decreases` to 55 pounds at which time contact22-22b of pressure responsive device PAS- 55 will open and willdeenergize valve Vl.

When the nrst axle of the car enters track section IT, track relay ITRwill pick up and will set intov operation the speed responsiveapparatus, which thereupon will start to function to measure the 'speedof the car. Furthermore, the entry of the nrst axle of the car intosection lT Will operate the weight responsive contact WRC, but since thecar'weighs less than 35 tons none of the contactsv of this contacterwill become closed, and all of theY weight responsive relays willtherefore remain deenergizedi. The car retarder will of cou-rse nowstart to slow down the car and if the car speed drops below 11.6 milesper hour which is the speed at which the relays 5U and lM become pickedup, the previously described pick-up circuit for relay lP will becomeclosed, and relays lP and vISP will become picked up. The picking up ofthese relays will complete the previously traced stick circuit for theserelays, and these relays Will therefore now remain energized until relaylPO picks up or until section lT becomes vacated even though the relays5U and lM of the speed responsive apparatus subsequently release.

The picking up of relay IP will also interrupt at its back contact23T-23M all circuits previously traced for valves Vl and V2 and willcomplete at its front contact 23l-23'lb another circuit for valve Vlpassing from terminal B through contact29 of lever L, Wires 28| and 235,back contact 23S-23m of relay IPO, front contact 231-2311) of relay lP,front contact 240-240b of relay LP, Wire 24l, contact 22-22b of pressureresponsive device P20-30, asymmetric unit 206 in its low resistancedirection, and the winding of valve Vl to terminal C. Valve Vl willtherefore become energized and will vent motor M to atmosphere. Valve Vlwill continue to vent motor M to atmosphere until the pressure in thecylinder 4- decreases to 30 pounds per square inch, at which timecontact 22-222) of pressure responsive device P20-30 will open and willdeenergize valve Vl. If the pressure in cylinder now decreases below 20pounds per square inch, the resultant closing of contact 22-22a ofpressure responsive device P20-30 will complete another circuit forvalve V2, and current will ilow from terminal B through contact 2'8 oflever L, wires 28| and 235, `back contact 23S-236e of relay IPO, frontcontact 23T- 2311 of relay lP, front contact 2ML-2Mb of relay LP, wire24I, contact 2.2-.22a of pressure responsive device P20-30, wire 205,and the winding I4 of valve V2 to terminalC. Valve V2 vwill thereforebecome energizedv and will connect .motor M. with pipe l1 until thepressure increases to 20 pounds per square yinch at which time contact22--2217V of pressureresponsive device P2II-3will open and will-de`energize valve V2. It will be seen, therefore, that when relay IPbecomes energized with relay LP energized, it functions to reduce thepressure of the fluidl in motor' M from a pressure of between 45 and55wpounds per square inchto a pressure of between 20 and 30 pounds.. persquare inch.

If the speed ofjthe car drops per hour while; the4 leading pair ofwheelsv 'is traversing section ITR, ythereby causing relays IU and 3M ofthe unit and multiple chains'of the speed responsive apparatus Ato bothbecome picked up, the previously traced circuit for relay IPO includingiront contact I'I` of relay IU. and iront contact 80 of relay 3Mwillbecome closed, and relays IPO andISPQ Will become picked up. Whenthese relays become picked up, one of the previously traced stick,circuits for these re. lays willv become closed, and all .of the stickcirbew= 6.7. Innes fcuits for the relays. IP and "ISP will becomeopened. The closing of the stick circuit forrelays IPO and ISPO= willcause these relays to remain energized untilsection ITR next becomesvacated, while ,the opening of the stick circuit for relays iP and ISPwill cause `these relays to release.

The picking'up ofV relay VIPO further inter rupts all circuitsypreviously"traced for valves VI and V2 and completes a circuit forvalve VIA passing from terminal B through contact 29` of lever L, Wires28| and 235,A` front Contact 236-2361) of relay IPO,'wirei2B3andthewinding I4 of valve-VI to terminal C. Valve V2 if it is notalreadyv deenergized when. this' circuit becomes closed `will becomedeenergiz'edgand valve VI will become energizedr to `thereby again ventiiuid from motor M to thereby effect the release of the retarder; Withthe retarder released, no further yretardation of the car will takeplace.

I shall now assume that with levervL in 'its'pI position and Awith relayIP yenergized theleading pair of wheels of the vcar passes out of'section ETR and into section 2TR. When'this happens, a new timingperiod vwill be initiatedr which will cause all of therelays of the unitand multiple chains to release, and the releasing of these relays, inturn, will interrupt the stick circuit which was previously closed forrelays IP Vand ESP at front'contact'2l5` of Yrelay 5U.y yRelay IP willtherefore become deenergizedybutdue to the condenser 22| andresistorv220 associated with this relay this relay will not release forar suicient interval of time to' permit a new vspeed measurement to bemade. fWlien'. this speed measurement has been madeifthespeed' of the fcar is still below the speed atwhich -relay VIP picks up butabove thespeedatwhichrelay IPO picksrup relay IP will ag'ainpick up," and theretarder will continue to retard'the car with` al brakingforcefcorresponding to a lpressure fof between and 30 pounds persquareinch in Cylinder M. f l Y -l l If lever L-remains"in its pl position land. the

speed of the car remains-less1fthan"-11.6-miles per hour butmorei-thanf- 6.1 miles per hour, a similar operation will take -placeeachftimethe measurementawhen .the next speed measurement is completedrelay IPO V will pick' up and will release the retarder.

VIi relayv IPOl is energizedwhen the .leading pair of wheels of the carpasses from` one trackfsec-v tion to the nextpthis relay will becomedeener` gizedbut will not releasedue to the slow'releasingcharacteristicsimparted to it by the con-` denser 224 and associatedresistances,- until a sufficient time interval' haselapsed to enable anew speeddetermination to be made.v If the car speed .has not increasedabove 6.1 miles per hour by the time the new speed measurement iscompleted, relay yIPO will become reenergized, andif the car speed hasincreased above 6.1 milesl per hour, relay IP willbecome'deenergized totherev by reapply the retarder. i'

When the leading pair ofwheels vacates sectionV 6T, the pair of Wheelsnext in rear will then function Vt0 operate the speed-responsiveapparatus in a manner which is fully described in the hereinbeforereferred to. Snavely application, 4

Serial No. 424,338.'

It follows, therefore, that when a car weighingr 'i less than 35 tonsproceedsl through the retarder,

i the speed responsive apparatus will function tov automaticallydecrease the braking pressure when the speed of the car decreases below11.6 miles i rspeed of 6.1 miles perhour. Likewise, after the desiredcontrol speed has been reached, the ap# 'paratus will then function toreapply' andrerelease the retarder if necessary to maintain this controlspeed.

`When'lever L occupiesV its 10| positionfand aV car weighing more than35 but less than 50 tons. 'Y

passes through the retarder, the relay WR35'Will Apick up and willtherebycaus'e 'the relaysIP and IPOtobecontrolled by the pick-upcircuits previously traced including iront;A contact '21S-'216e of relayrWRSB, so that under these conditions relay IPfwill pick up andwillvdecrease'thenbraking force exerted by the retarder when vthe car speedhas decreased below 9.8 miles per hounand lrelay IPO willpick 'up'andrelease theretarder. whenV the car speed decreases below"5.3' miles`per` hour. Except for the fact that .a different set of pickfupcircuits is effective for controlling lthe relays'IP and IPO underthese' conditions,. the operation is otherwise vthe same as thatdescribed.

above, and it is believed to be unnecessary therefore .to describethisoperation in detail; C .l -If` a, `car weighing morethan wtonsbut lessvthan '70 tons .passes through the retarder when lever ,L occupiesitsp'l position, the resulting pickingup of relay WR50 will render the sameset of pick-.up circuitseiiective for controllingv relays K vIPyandIPQas are effective when a car weighing morejthantons but.lessthan 50 tons passes lthrough the retarder, butunder `theseconditions,

the opening of back contact 289 of relay WR willcause relay LP to becomedeenergized.f-As alresiult. as long as the speed off the car is suf-yciently high sojthat .relays 'IP and IPO are'both Ldeenergized, valve V2will 'become energizedove'r thecircuit frst traced vforvlthis valve; andWill y leading pair of wheels entersa4 new-track seci Likewise, if thecar slows down suiliciently between speed thereby cause motor M tov besupplied. with. fluid at full line pressure.

When the speed of the car decreases below the speed at which relay IPpicks up, the resulting picking up of this relay will: interruptthecircuit for valve V2, and will complete a circuit for valve VIpassing from terminal B through contact Z9 of lever L, wires 28|' and235, back contact 236--236a of relay IPO, front Contact 23T-2311) ofrelay IP, back contact 24U- 240D of relay LP, wire 23S, contact 22-221)of pressure responsive device PLIS-55, asymmetric unit G in its lowresistance direction, and the winding I 4 of valve Vl to terminal C.Valve VI will therefore become energized and will vent iluid fromk motorM until the pressure decreases to 55 pounds per square inch, Wheny thishappens contact 22-2211 oi pressurefresponsive device PGE-55 will openand will' deenergize valve VI. If the pressure in rnc-tor' M nowdecreases below 45. pounds per square inch, valve V2 will again becomeenergized over a circuit which passes from terminal B through contact 2Qof lever L, wires Zaly and 235, back contact 23E-235e of relay IPO,front contact 23l-23'Ib of relay IP, back contact 24U- 249D of relay LP,wire 239, Contact 22-22a of pressure responsive device PILE-55, wire2D5, and the winding of valve V2 to terminal C.

i If the speed of the car decreases below 5.3 miles per hour, so thatrelay IPO picks up, valve VI will become energized and will vent fluidfrom motor M to release the retarder in the same manner as when a lightweight car traverses the retarder.

It will be seen, therefore, that when lever L occupies its pl positionand a car weighing more than 50 but less than '70 tons traverse theretarder, the motor M will be'supplied with fluid. at full line pressureas long as the speed of the car is above the speed of 9.8 miles per hourwhich is the speed at which relay IP picks up under these conditions,and that when the car speed drops below this speed, the picking up ofrelay I-P will function to reduce the pressure of the Huid supplied tomotor M to a pressure of between4 45 and 55 pounds per square inch.Furthermore, when the car speed decreases below 5.3 miles per hour,relay IPO will pick up and will release the retarder.

When lever L occupies its pl position and a car in excess of '70 tonstraverses the retarder, the operation of the apparatus will be the sameas for a car weighing more than 50 but less than 70 tons except for thefact that under these conditions relay WRT will pick up and will renderstill a different set of pick-up circuits eiective for controllingrelays IP and IPO. These pickup circuits were traced hereinbefore, andfunction to cause relay IP to pick up and decrease the braking forceexerted by the retarder when the carspeed decreases below 9.1 miles perhour, and relay IPO to pick up and release the retarder when the carvspeed decreases below'miles per hour. t will be noted that under theseconditions relay LP is caused to release by virtue of the opening ofcontact 286 of relayk WR'IU'.

When lever L is moved to its p3 position, the speed responsive andweight responsive apparatus is rendered ineffective. to control therelays IP and IPO so that these relays. both. remain deenergizecl. RelayLP, however, is still. controlled by the weight responsive relays WR50and WR'IIJ so that relay will be rpicked. up when cars weighing less.than 50 tons traverse the retarder and will be released when heaviercars traverse the retarder. With relays IP and IPO d'eenergized, whenrelay LP is released, valve V2 will remain constantly energized byvirtue of the previously traced circuity for this valve, so that motor Mwill be supplied with fluid at full linepressure; When relay LP ispicked up, however', the pressure responsive device P45-55 will then berendered eiective to control the valves VI and V2, and motor M willtherefore be supplied with fluid at a pressure of between 45 and 55pounds per square inch.

One advantage of apparatus embodying my invention isv that since eachcar can be made to leave the retarder at the moet desirable speed forthe particular car weight, all elements of control' of the retarderrequiring skill in judging car speed, etc., are eliminated, whereby thecar retai-der yard as a whole can be worked at the highest efficiencywithout the necessity for specially trained operators.

Moreover, since the most desirable coupling speeds are obtained due tothe combination of speed and weight control, there is less likelihood ofdamage to cars and their contents caused by excess coupling speeds whenthe cars reach their destination in the classication tracks.

Another advantage of apparatus embodying my invention is that it is veryflexible, and readily lends-itself to varying yard conditions.

Although I have herein shown and described only one form of railwaybraking apparatus embodying my invention, it is understood that variouschanges and modications may be made therein within the scope of theappended claims without departing from the spirit and scope of myinvention.

Having thus described my invention, what I claim is: l. In combinatiomacar retarder, means controlled by the weight of a car passing throughthe retarder for controlling the braking force exerted by the retarderto cause the retarder to exert a higher braking. force for heavy carsthan it exerts for light cars, means controlled by the speed of a carpassing through the retarder for decreasing the braking force exerted bythe retarder as the car speed approaches any one of a plurality ofselected control speeds and for releasing the retarder ifthe car speeddecreases to the selected speed, and means automatically controlled bythe weight of a car passing through the retarder for automaticallyselecting the control speed to cause cars to leave the retarder atspeeds which are inversely proportional to the car weight.

2. In combination, a car retarder, means for Weighing cars passingthrough the retarder, means for repeatedly measuring the speed of carspassing through the retarder, and means controlled jointly by saidweighing and speed measuring means for controlling the braking action ofsaid retarder to cause cars to leave the retarder at selected controlspeeds which are inversely proportional to the car Weights.

3. In combination, a fluid pressure operated car retarder, meanscontrolled by the weight of a car passing through said retarder forsupplying said retarder with iiuid at a pressure which is` proportionaltothe car weight, and means controlled jointly by the weight and speedof a car passing through said retarder for decreasing the pressure oftheiiuid supplied to said car retarder in selected amounts asl the carspeed decreases. to cause cars to leave the retarder at rspeeds whichare inversely proportional to the car weights.

4. In combination, va fluid pressure operated car retarder, meanscontrolled 'by the weight of a portional to the rcar weight. f

5. In combination, a iiuid pressure operated 'l rcar retarder, meanscontrolledby the Weight of a car entering the retarder for initiallysupply-l ing the retarder with Iiuid at a pressure which depends uponthe car weight, and means for sub-j sequently reducing the pressure ofthe Huid supplied to said retarder whenthe speed of the carV hasdecreased to a speed which is inversely pro portional to thecar weight.y

6. In combination, afcar retarder, meanscontrolled by the weight of acar entering the retarder for causing said car retarderfto exert apredetermined braking force which depends upon the car weight and whichis greater for heavy cars than for light cars, and means controlled bythe weight and speed of the car for` Subsc quently reducing said brakingforce when the car speed has been reduced to a speed which depends uponthe car weightr and which is inversely proportional tothe car weight.

'7. In combination, a car retarder, means for,V

causing said car retarder to exert a plurality of different brakingforces, vmeans automaticallycontrolled by the weight of a car enteringthe retarder for initially selecting the level of the braking force, andmeans controlled by the speed of the car for subsequently decreasing thebraking force if the speed of the car decreases below a iirst speed andfor releasing the retarder if it decreases below a second speed.

8. In combination, a stretch of railway track,

fluid pressure operated braking apparatus for retarding the speed of acar traversing said stretch,`means for supplyingA said apparatus withfluid at a selected one of a. plurality of predeterv`mined pressures,said selection beingv effected automaticallyin accordance with theweight of vthe car, means controlled by the speed of the car l. forsubsequently reducing the pressure if the car speed decreases below oneof a plurality of vpredetermined speeds, and means for selecting suchpredetermined speed automatically inl inverse yproportion to the carweight. f v i 9. In combination, a car retarder, a plurality of relays,means for selectively energizing said relays in accordance with theweightof a car entering said retarder, `and means for releasing saidretarder at a plurality of different speeds depending upon which one ofsaid relays becomes energized.

10. In combination, a car retarder,v a first, a' second, and a thirdrelay, means for causing saidv car retarder to exert a rst braking forcewhen all three yof said relays are deenergized, means for decreasingsaid braking force a first amount if said first relay becomes energizedwhen said second relay is deenergized anda second amount if said rstrelay becomes energized when said second relay is also energized, meansfor releasing said retarder when said third relay becomes energized,means for energizing said second relay when cars weighing less 'than apredetermined weight are being retarded by said retarder Aand fordeenergizing said relay when cars above said predetermined weight arebeing retarded by said' retarder, means for renergizing said first relaywhen the speed of a car Itraversing' said retarder 1 decreases below airst predetermined speed, and

other means for energizingsaid third relayk when the speed of a cartraversing said retarderde-V creases below a second predetermined speed.

11. In combination,'a car retarder, a rst, a

second, and a third relay, meansfor causing said car retarder to exert aiirst braking force when.

all three of said relays are deenergized, means for decreasing saidbraking force a rst amount` if said first relay becomesenergizedwhen'said second relay is deenergized and a second amount -if fsaid rstrelay becomes energized when said weight` responsive relays forcontrolling said second A,relay is also energized, means forreleas-ringlsaid retarder when said third relay becomes energized, speedresponsive apparatus including a plurality of relays which pick upselectively in response Vtothe speed of a car being retardedby' said.,rretarder, a 'pluralityy of other relays which pick up selectively inresponse to the weightk of a car being retarded `by said retarder, andmeans controlled jointly by thejrelays of said speed` responsiveapparatus and 'said weight responsivey relays Vfor selectivelycontrolling said iirstand third relays, and other'means .controlled by`said second relay.

12. Incornbinatiom a car retarder, a first, a' second, anda third relay,means for causing said car retarder to exert a first braking force when1 all three of said relays are deenergized, means for decreasing saidbraking force a first amount if said rst relay 'becomesenergized whensaid second relay is deenergized and a second amount Y if said rst relaybecomes'energized whensaid"I second relay is also energized, means forreleasing said retarder when said `third relay becomes energized,` speedresponsive apparatus including a pluralityof relays which pickupselectively in response tothe speed of avc'ar being retarded by Y l saidretarder, a plurality of other relays which n. pick up selectively inresponse to the weight of a car being retarded by said retarder,means'cony trolled jointly by the relays of saidspeed responsive apparatusand said-weight responsive relays for selectively controlling said firstand third` relays in such manner that said first relay will pick up whenthe speed of a car being retarded 'by the car decreases to one of aplurality of pre- 1 determined speeds which depends uponthe car weightand that said third relay will Ypick upV when the speed-cf a cardecreases to one of a plurality of predetermined speeds each'of whichalso depends upon the car weight and each of which for any given carweight is less than the speed at which said first relay picks up, andother means controlled by said weight responsive relays for controllingsaid secondrelay. y I

JOHNKW. LOGAN, Ja.'

